This had long been a point of confusion. Connecticut families tend to be Congregationalist by default prior to 1818; if they were not, they were often Baptist or Episcopal. Yet, when families migrated to new regions they often ended up in the Presbyterian Church.
As it turns out, there’s a reason for the switch. In 1801, the Presbyterian Church entered into a “Plan of Union” with the Congregational Church, essentially allowing the two denominations to work together. The resulting church may have ended up being either Congregational or Presbyterian.
If you “lose” a Connecticut family, and there’s no Congregational Church in the area – try the Presbyterian.
Connecticut Roots by Charter Oak Genealogy 